<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>多类名</title>
    <style>
    .red {
        color: red;
    }
    .format {
        font-size: 100px;

    }
    </style>
</head>
<body>
    <div class="red format">刘德华</div>
</body>
</html>